High Energy Physics

Research Projects:

ATLAS is a multi-purpose detector at the Large Hadron Collider at the CERN laboratory in Geneva, Switzerland. It is a general-purpose detector, with some of the primary goals being to look for the Higgs boson and study its properties if it is found, to look for supersymmetric particles, and to look for new physics such as extra dimensions and mini black holes. The collaboration consists of over 3000 physicists and engineers from 18 countries.

BaBar is a detector at the SLAC National Accelerator Laboratory in Stanford, CA. It took data from 2000 to 2009, with analysis continuing. The primary physics goal is to study in detail symmetry-breaking properties of the weak interaction. The name BaBar® is used by permission from Laurent. deBrunhoff.

D0 is a detector at the Tevatron Collider at theFermi National Accelerator Laboratory near Batavia, IL. Until recently, the Tevatron Collider provided the highest energy collisions in the world. The research is focused on precise studies of interactions of protons and antiprotons at the highest available energies, with a particular emphasis on searching for the Higgs boson.

The experimental neutrino group is doing research on neutrino oscillations using long baseline experiments such as MINOS, NOvA and LBNE. These US-based experiments send beams of neutrinos from Fermilab to be caught by very large particle physics detectors hundreds of miles away. This work allows us to measure crucial properties of neutrino mixing that could open the door to a better understanding our Universe.

Next is a delicate search for neutrino-less double-beta decay in the Canfranc tunnel under the Pyrenees mountains. This experiment is very new and uses 100 kg of enriched Xenon isotope-136 at 15 atmospheres pressure in a large TPC (Time Projection Chamber) with electroluminescent gain. The energy resolution is already tested at better than 0.5% and, combined with the 3-dimensional imaging of a TPC, we expect to be the best in the world.

Theory (Valencia, Whisnant)

The theory group works on a variety of problems, including phenomenological research in electroweak interactions within the standard model and beyond, and the study of the phenomenology of neutrino interctions.

It’s Officially a Higgs Particle!

The particle announced at CERN in July 2012 was described as a “Higgs candidate” because not enough was known about its properties to make a positive identification. With further data and more careful analysis the ATLAS and CMS collaborations at CERN now positively identify it as a Higgs particle. Measurements of its spin, parity, and additional decay rates made this possible. Note, however, that it is a Higgs particle, not necessarily the Higgs particle, since many theories – especially Supersymmetry – predict a family of Higgs particles, of which this would be the lightest. The hunt for heavier Higgs particles will be a major part of the program when the LHC resumes operation after the present long shutdown to upgrade its energy. Physics is expected to resume in late 2014 or early 2015.

Higgs Excitement

The ISU High Energy Physics group is proud to be part of the ATLAS collaboration, one of two research teams at the CERN laboratory that recently announced the discovery of a likely candidate for the Higgs particle. First predicted in 1964 as a way to give mass to elementary particles, the Higgs has been sought for decades. Its discovery, if verified, opens the path to new areas of research. Iowa State has been collaborating on the ATLAS experiment at CERN since 1999. Many publications have chosen this as the discovery of the year.

Experimenters have sought the Higgs since 1964, looking at ever larger masses. The latest discovery of a particle with a mass of about 126 billion electron volts (GeV), is the first positive result. The discovery of the Higgs is not the end of the road. Studying the decay modes and lifetimes of the Higgs will further test the theory. A leading extension of the standard model, called supersymmetry, predicts there will be at least five Higgs particles, two of them electrically charged.

Mayly Sanchez wins Presidential Early Career Award

The White House announced on July 16, 2012, that faculty member Dr. Mayly Sanchez has been awarded the Presidential Early Career Award for Scientist and Engineers. This is the highest honor awarded by the U.S. government to science and engineering professionals in the early stages of their research careers.

BaBar Experiment Observes Time-reversal Violation

It has been believed for over fifty years that time-reversal in Physics is not a valid symmetry, but a direct measurement of time reversal violation has not been possible until now. In a clever analysis the BaBar experiment at SLAC has finally made a direct measurement that yields a result at the expected level. This result was chosen by Physics World Magazine as the third most important result of 2012.